Portable RFID reading terminal with visual indication of scan trace

ABSTRACT

A method of reading RFID tags may include providing a device that can read barcodes and RFID tags. The barcodes may be attached to an object and respectively having a predetermined sequential read order. While reading the barcodes in the predetermined sequential read order, outputting an interrogation signal to RFID tags so that the RFID tags can be read while the barcode reader moves to sequentially read the barcodes in the predetermined sequential order.

CROSS-REFERENCE TO RELATED APPLICATION

This nonprovisional application claims the benefit of U.S. ProvisionalApplication No. 62/098,748 filed Dec. 31, 2014.

FIELD

Embodiments of the invention are generally related to encodedinformation reading (EIR) terminals and is specifically related to RFIDreading terminals including radio-frequency identification (RFID)reading devices.

BACKGROUND

RFID methods are widely used in a number of applications, includingsmart cards, item tracking in manufacturing, inventory management inretail, etc. An RFID tag can be attached, e.g., to an inventory item. AnRFID reading terminal can be configured to read the memory of an RFIDtag attached to an inventory item.

Additionally, in a retail sales environment, the use of handheld RFIDreading devices to perform department inventory offers the potentialbenefits of performing such inventory operations more quickly thanmanual inventorying and hence at a lower cost, as well as improving theaccuracy of inventory counts.

However, there are drawbacks to this approach. Indeed, studies haveshown these potential benefits of using RFID methods are only partiallyrealized, mainly due to incomplete coverage of merchandise on fixturesin the retail department. As a result, inaccurate inventory counts arerecorded using at least some RFID methods, leading to sub-optimalrevenue (i.e. due to over- or under-stocking resulting from theinaccurate inventory counts).

What is needed is a system and method for determining what portions of agiven retail fixture have been properly inventoried using a handheldRFID reader. Such a system would ideally be easily integrated intoexisting handheld RFID reader products. As a result, the potentialbenefits of using handheld RFID reading devices for inventory operationswill be realized to a much greater extent, increasing the revenue of theretail establishment.

SUMMARY

In one embodiment, there is provided a portable radio-frequencyidentifier (RFID) reading terminal comprising a microprocessor, amemory, an RFID reading device including a radio frequency (RF) antenna,and a display. The portable RFID reading terminal can be configured todisplay a scan trace provided by a line comprising a plurality of timevarying points. Each point can be defined by a projection of thecoverage shape of an RF signal transmitted by the RFID reading deviceonto a chosen plane at a given moment in time.

In one embodiment, the portable RFID reading terminal can, by readingRFID tags attached to the items, reconcile a count of items stored in amanufacturing, retail, and/or storage facility against an expected countwhich can be received, e.g., from an external computer. In anotherembodiment, the portable RFID reading terminal can, by reading RFID tagsattached to the items, reconcile an inventory of items stored in amanufacturing, retail, and/or storage facility against an expectedinventory list received, e.g., from an external computer. In a furtheraspect, the portable RFID reading terminal can transmit to the externalcomputer the list or the count of read RFID tags.

In one embodiment, the portable RFID reading terminal can furthercomprise a two-dimensional imager. The portable RFID reading terminalcan be further configured to determine a spatial position of the RFsignal coverage shape based on a known position and orientation of theRF antenna relative to the position of the field of view of thetwo-dimensional imager.

In one embodiment, the portable RFID reading terminal can be furtherconfigured to measure a distance to an object using the two-dimensionalimager. The portable RFID reading terminal can be further configured todetermine and display the projection of the RF signal coverage shapeonto the plane defined by the physical structure which in one embodimentcan contain a plurality of inventory items.

In one embodiment, the portable RFID reading terminal can furthercomprise at least one accelerometer. The portable RFID reading terminalcan be further configured to determine a change of the spatial positionand orientation of the RF signal coverage shape based on the properacceleration values received from the accelerometer.

In one embodiment, the portable RFID reading terminal can be configuredto display a quantity of scanned items, a quantity of items which havenot be scanned yet, and/or a total quantity of items to be scanned.

In one embodiment, the portable RFID reading terminal can be configuredto display an indicator of a ratio of quantity of scanned items to atotal quantity of items to be scanned.

In one embodiment, the portable RFID reading terminal can be configuredto display a scan trace overlaid over an image of a physical structurewhich can contain one or more scanned items and/or one or more items tobe scanned. In a further aspect, the image of the physical structure canbe acquired by the two-dimensional imager or received from an externalcomputer. In one embodiment, portable RFID reading terminal can beconfigured to receive a description of the physical structure, andcreate an image of the physical structure based on the description.

In one embodiment, the portable RFID reading terminal can be configuredto display an indicator of an RF signal coverage over a scan traceoverlaid over an image of a physical structure.

In one embodiment, the portable RFID reading terminal can be configuredto display an indicator of an RF signal coverage over a current positionwithin the scan trace.

In some embodiments, a handheld system uses an optical barcode scannerand a handheld RFID reader in a single device to estimate a scan path ofhandheld RFID reader when performing retail inventory. This is performedby scanning custom barcodes indicating the location of barcode onfixture and guiding the user to a path to move the handheld RFID reader.

In one embodiment, a system for reading RFID tags may include: a barcodereader that projects a light to read barcodes attached to an object in apredetermined sequential order; and an RFID reader comprising an antennathat reads RFID tags while the barcode reader moves to sequentially readthe barcodes in the predetermined sequential order along the object;wherein an RFID scan path of the object is determined based on scanningthe barcodes in the predetermined sequential order.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, the drawings show aspectsof one or more embodiments of the invention. However, it should beunderstood that the present invention is not limited to the precisearrangements and instrumentalities shown in the drawings, wherein:

FIG. 1 schematically illustrates a scan trace displayed by an RFIDreading terminal;

FIG. 2 schematically illustrates an RF signal coverage shape by the RFIDreading terminal;

FIG. 3 schematically illustrates a component-level diagram of oneembodiment of the RFID reading terminal;

FIG. 4 schematically illustrates a network diagram of one embodiment ofa data collection system employing RFID reading terminals;

FIGS. 5a-5b schematically illustrate determining a spatial position ofthe RF signal coverage shape based on the known position and orientationof an RF antenna relatively to the position of the field of view of atwo-dimensional imager;

FIGS. 6-19 schematically illustrate various methods of displaying scantraces and selected inventory quantities by the RFID reading terminal;

FIGS. 20a-20c schematically illustrate embodiments of an RFID readingterminal.

FIG. 21 illustrates a scan trace displayed by an RFID reading terminalusing a point-based scan path determination in accordance with anembodiment.

FIG. 22A illustrates a scan trace displayed by an RFID reading terminalusing a point-based scan path determination in accordance with anembodiment.

FIG. 22B illustrates a scan path point table used in conjunction withFIG. 22A in accordance with an embodiment.

FIG. 23A illustrates a scan trace displayed by an RFID reading terminalusing a point-based scan path determination with positions of thedecodable indicia similar to that of FIG. 22A in accordance with anembodiment.

FIG. 23B illustrates a scan trace displayed by an RFID reading terminalusing a point-based scan path determination with different positions ofthe decodable indicia in accordance with an embodiment.

The drawings are not necessarily to scale, emphasis instead generallybeing placed upon illustrating the principles of the invention. In thedrawings, like numerals are used to indicate like parts throughout thevarious views.

DETAILED DESCRIPTION

RFID reading devices usually offer improved efficiency over barcodescanning devices for retail inventory, by being capable of readingmultiple RFID tags that are within range of the RF signal transmitted byan RFID reading device. A downside to this multiple-read capability islack of scanned items localization, due to insufficient correlationbetween where the RFID reader is located or oriented, and the RFID tagsbeing read. Retail inventory management typically requires more than 90%of the RFID tags present in a department to be successfully acquiredduring the inventory process. When this high accuracy is not achieved,it is necessary to rescan the entire department, since the locations ofany unread RFID tags are unknown.

In one embodiment, there is provided a portable radio-frequencyidentifier (RFID) reading terminal configured to present a visualindication of defined areas which have been scanned and areas which havenot been scanned for RFID tags. Such a capability provides increasedoperational efficiency of RFID tag reading for retail inventorymanagement. Various embodiments of the RFID reading terminal can be usedin a numerous applications, including but not limited to, item trackingin manufacturing, storage, and retail, real-time inventory controlsystems, etc.

Item tracking and/or inventory control can be implemented by placing anRFID tag on each inventory item. The RFID reading terminal can compriseat least one RFID reading device which can be configured to read and/ormodify a memory of an RFID tag containing an encoded message. The RFIDreading device can transmit and/or receive radio frequency (RF) signalsto and from RFID tags attached to inventory items. Each RFID tag canstore the tag identifier in its memory. An RFID tag attached to aninventory item can further store in the tag's memory a product code ofthe item, an EPC (Electronic Product Code) of the item, and/or at leastone alphanumeric string identifying the item.

The RFID reading device can be further configured to output decodedmessage data corresponding to the encoded message, e.g., decoded messagedata containing identifiers of the items to which the RFID tags areattached. The RFID reading terminal can be configured to store in itsmemory and/or transmit to an external computer the item identifiersreceived from the plurality of RFID tags.

In a further aspect, the RFID reading terminal can be configured toreceive an expected count of inventory items or an expected inventorylist of items of interest stored within a storage, manufacturing, and/orretail facility. As used herein, “inventory list” shall refer to acollection of item descriptions, each item description comprising atleast the item identifier.

In one embodiment, the RFID reading terminal can receive the expectedcount of inventory items or the expected inventory list over a networkfrom an external computer. In another embodiment, the RFID readingterminal can receive the expected count of inventory items or theexpected inventory list via the user interface. In a yet anotherembodiment, the RFID reading terminal can receive the expected count ofinventory items or the expected inventory list by reading an externalmemory device connected to one of the terminal's I/O ports (e.g., a USBport, or a PCMCIA interface). In a yet another embodiment, the RFIDreading terminal can be equipped with a 2D imager and can receive theexpected count of inventory items or the expected inventory list via the2D imager, for example, by scanning a plurality of optical decodableindicia (e.g., a plurality of bar codes), or by acquiring an image of atextual document containing the expected count of inventory items or theexpected inventory list and then processing the image using opticalcharacter recognition (OCR) methods.

The RFID reading terminal can be further configured to reconcile theinventory of items stored within a storage, manufacturing, and/or retailfacility against the expected count of inventory items or the expectedinventory list by reading the RFID tags attached to the inventory items.

The RFID reading terminal can read RFID tags from a range of distancesand various terminal orientations with respect to an RFID tag beingread. To further improve the reliability of scanning operations and theterminal's operator experience, the RFID reading terminal can beconfigured to emit audible signals (e.g., beeps) to indicate anoccurrence of a pre-defined event, thus providing an audible feedback tothe operator of the RFID reading terminal. In one embodiment, the RFIDreading terminal can be configured to emit an audible signal of a firsttype every time a unique RFID tag has been successfully read andreconciled against an inventory list. The RFID reading terminal can befurther configured to and emit an audible signal of a second type everytime a unique RFID tag has been successfully read but failed toreconcile against the inventory list. The RFID reading terminal can befurther configured to emit an audible signal of a third type every timea pre-defined timeout has elapsed without reading an RFID tag. However,the audible feedback inherently fails to indicate the location of theRFID tag having been successfully read.

To further improve the readability of scanning operations, the RFIDreading terminal can in one embodiment be configured to display on theterminal's display one or more scan traces, thus providing theterminal's operator with a visual feedback with respect to the scanningprogress, as schematically shown in FIG. 1.

At any moment in time, the RF signal coverage emitted by an RFID readingterminal can be defined by a 3D shape, as schematically shown in FIG. 2.The form and size of the 3D shape defining the RF signal coverage candepend, among other factors, on the RFID transmit power level and thenumber and configuration of the RF antennas employed by the RFID readingdevice. In one embodiment, the 3D signal coverage shape can be providedby a sphere 2020. In another embodiment, the 3D signal coverage shapecan be provided by an ellipsoid. In a yet another embodiment, the 3Dsignal coverage shape can be provided by a cone.

At any given moment in time, a target scan area by an RFID readingterminal can be visualized as a projection 2040 of the 3D RF signalcoverage shape 2020 onto an arbitrarily chosen plane 2050, including animaginary plane. For a moving RFID reading terminal, a visual scan tracecan be provided by a line defined by a multitude of time varying points,each point being a projection 2040 of the 3D RF signal coverage shape2020 onto the arbitrarily chosen plane 2050 at a given moment in time.

In a further aspect, the imaginary plane onto which the visual scantrace is projected can be chosen to intersect a physical structure(e.g., a shelf) containing the inventory items, and thus the scan tracecan be overlaid over an image of the physical structure as schematicallyshown in FIG. 1.

Component-level diagram of one embodiment of the RFID reading terminalis now being described with references to FIG. 3. The RFID readingterminal 100 can comprise at least one microprocessor 310 and a memory320, both coupled to the system bus 370. The microprocessor 310 can beprovided by a general purpose microprocessor or by a specializedmicroprocessor (e.g., an ASIC). In one embodiment, RFID reading terminal100 can comprise a single microprocessor which can be referred to as acentral processing unit (CPU). In another embodiment, RFID readingterminal 100 can comprise two or more microprocessors, for example, aCPU providing some or most of the RFID reading terminal functionalityand a specialized microprocessor performing some specific functionality.A skilled artisan would appreciate the fact that other schemes ofprocessing tasks distribution among two or more microprocessors arewithin the scope of this disclosure.

RFID reading terminal 100 can further comprise a communication interface340 communicatively coupled to the system bus 370. In one embodiment,the communication interface can be provided by a wireless communicationinterface. The wireless communication interface can be configured tosupport, for example, but not limited to, the following protocols: atleast one protocol of the IEEE 802.11/802.15/802.16 protocol family, atleast one protocol of the HSPA/GSM/GPRS/EDGE protocol family, TDMAprotocol, UMTS protocol, LTE protocol, and/or at least one protocol ofthe CDMA/1xEV-DO protocol family.

RFID reading terminal 100 can further comprise a battery 356. In oneembodiment, the battery 356 can be provided by a replaceablerechargeable battery pack. The RFID reading terminal 100 can furthercomprise a GPS receiver 380. The RFID reading terminal 100 can furthercomprise at least one connector 390 configured to receive a subscriberidentity module (SIM) card.

The RFID reading terminal 100 can further comprise an imaging device330, provided, for example, by a two-dimensional imager.

The RFID reading terminal 100 can further comprise an RFID readingdevice 333. In one embodiment, the RFID reading device 333 can beconfigured to read a memory of an RFID tag containing an encoded messageand to output raw message data containing the encoded message. Inanother embodiment, the RFID reading device 333 can be configured toread a memory of an RFID tag containing an encoded message and to outputdecoded message data corresponding to the encoded message. As usedherein, “message” is intended to denote a bit sequence or a characterstring comprising alphanumeric and/or non-alphanumeric characters. Anencoded message can be used to convey information, such asidentification of the source and the model of an item, for example, inan EPC code.

In one embodiment, the RFID reading terminal 100 can further comprise agraphical user interface including a display adapter 175 and a keyboard179. In one embodiment, the RFID reading terminal 100 can furthercomprise an audio output device, e.g., a speaker 181.

It is not necessary that a device's primary function involve readingRFID tags in order to be considered an RFID reading terminal; forexample, a cellular telephone, a smart phone, a PDA, or other portablecomputing device that is capable of reading RFID tags can be referred toas an RFID reading terminal for purposes of this disclosure.

In a further aspect, the RFID reading terminal can be incorporated in adata collection system. One embodiment of the data collection system,schematically shown in FIG. 4, can include a plurality of RFID readingterminals 100 a-100 z in communication with a plurality ofinterconnected networks 110 a-110 z.

An RFID reading terminal 100 a-100 z can establish a communicationsession with an external computer 171. In one embodiment, network framescan be exchanged by the RFID reading terminal 100 and the externalcomputer 171 via one or more routers 140, access points 135, and otherinfrastructure elements. In another embodiment, the external computer171 can be reachable by the RFID reading terminal 100 via a local areanetwork (LAN). In a yet another embodiment, the external computer 171can be reachable by the RFID reading terminal 100 via a wide areanetwork (WAN). In a yet another embodiment, the external computer 171can be reachable by the RFID reading terminal 100 directly (e.g., via awired or wireless interface). A skilled artisan would appreciate thefact that other methods of providing interconnectivity between the RFIDreading terminal 100 and the external computer 171 relying upon LANs,WANs, virtual private networks (VPNs), and/or other types of network arewithin the scope of this disclosure.

A “computer” herein shall refer to a programmable device for dataprocessing and control, including a central processing unit (CPU), amemory, and at least one communication interface. For example, in oneembodiment, a computer can be provided by a server running a singleinstance of a multi-tasking operating system. In another embodiment, acomputer can be provided by a virtual server, i.e., an isolated instanceof a guest operating system running within a host operating system. A“network” herein shall refer to a set of hardware and softwarecomponents implementing a plurality of communication channels betweentwo or more computers. A network can be provided, e.g., by a local areanetwork (LAN), or a wide area network (WAN). While different networkscan be designated herein, it is recognized that a single network as seenfrom the application layer interface to the network layer of the OSImodel can comprise a plurality of lower layer networks, i.e., what canbe regarded as a single Internet Protocol (IP) network, can include aplurality of different physical networks.

The communications between the RFID reading terminal 100 and theexternal computer 171 can comprise a series of requests and responsestransmitted over one or more TCP connections. A skilled artisan wouldappreciate the fact that using various transport and application levelprotocols is within the scope and the spirit of the invention.

At least one of the messages transmitted by the RFID reading terminal100 can include decoded message data corresponding to an RFID labelattached to an inventory item. For example, an RFID reading terminal cantransmit a request to the external computer to retrieve productinformation corresponding to a product identifier encoded by an RFID tagattached to a retail item, or to transmit an item tacking record for anitem identified by an RFID tag attached to the item.

As noted herein supra, the RFID reading terminal 100 can be configuredto receive from the external computer 171 an inventory list containingitem identifiers, or count, of items stored within a storage,manufacturing, and/or retail facility. The inventory list or count canfurther contain storage location information of specific items. The RFIDreading terminal 100 can be further configured to reconcile an inventoryof items stored in a manufacturing, retail and/or storage facilityagainst the inventory list or count, by reading RFID tags attached tothe items. The RFID reading terminal 100 can be configured to transmitthe reconciled list or count to the external computer 171.

The RFID reading terminal 100 can be further configured to display ascan trace on the terminal's display, thus providing to the operator avisual feedback with respect to the scanning progress. In oneembodiment, one or more scan traces 111 a, 111 b can be overlaid over animage of physical structure 115 containing the inventory items asschematically shown in FIG. 1. In a further aspect, for a moving RFIDreading terminal, a visual scan trace can be provided by a line definedby a multitude of time varying points, each point being a projection ofthe 3D RF signal coverage shape onto a plane defined by the physicalstructure 115 containing the inventory items at a given moment in time.

A noted herein supra, in one embodiment, the RFID reading terminal cancomprise a two-dimensional imager. The RFID reading terminal can beconfigured to determine a spatial position of the RF signal coverageshape based on the known position and orientation of the RF antennarelatively to the position of the field of view (FOV) of thetwo-dimensional imager, as schematically shown in FIGS. 5a -5 b.

The plane 2050 can represent an arbitrary chosen plane, e.g., a planeintersecting a physical structure hosting one or more inventory items.The RF antenna can be oriented relatively to the view finder in such away that the central axis 5010 of the field of view of the imager wouldbe parallel to the central axis 5020 of the RF signal coverage shape bythe antenna. Reducing the distance between the RFID reading terminal andthe plane 2050 and/or increasing the RF transmit power level results ina larger projection of the RF signal coverage area onto the plane 5020,as schematically shown in FIGS. 5a -5 b. In the example of FIG. 5b , thelesser distance and/or the greater transmit power level results in alarger projection RF signal coverage area onto the plane 5020. Theprojection of the RF signal coverage shape onto the plane 2050 can beentirely within the FOV of the two-dimensional imager, as schematicallyshown in FIG. 5a , or can be partially outside of the FOV of thetwo-dimensional imager, as schematically shown in FIG. 5 b.

In a further aspect, the RFID reading terminal can be configured tomeasure the distance to an object using a two-dimensional imager. Basedon the known shape of the signal coverage and the distance andorientation of the RF antenna to a physical structure 115 containing theinventory items, the RFID reading terminal can determine and display theprojection of the 3D RF signal coverage shape onto the plane defined bythe physical structure 115.

In another embodiment, the RFID reading terminal can comprise one ormore accelerometers and can be configured to determine the change of thespatial position and orientation of the RF signal coverage shape basedon the proper acceleration values received from the accelerometers. Inone illustrative embodiment, the RFID reading terminal can comprisethree or more accelerometers.

In one embodiment, the RFID reading terminal 100 can be furtherconfigured to display a quantity of scanned items, a quantity of itemswhich have not been scanned yet, and/or a total quantity of items to bescanned, the latter quantity determined based on an inventory count orlist of items describing a storage, manufacturing, and/or retailfacility. A progress indicator 191 of FIG. 1 shows the number of itemsscanned and the total number of items expected to be scanned. In anotherembodiment, the RFID reading terminal 100 can be further configured todisplay a both an absolute progress bar 192 a, and/or a relativeprogress bar 192 b indicating a quantity of scanned items and a totalquantity of items expected to be scanned, as shown in FIG. 6.

In one embodiment, the RFID reading terminal 100 can be furtherconfigured to display an indicator 119 of the RF signal coverage over ascan trace, as schematically shown in FIG. 7. The indicator of the RFsignal coverage can be determined as a line being a projection of the 3DRF signal coverage shape onto a plane defined by the physical structure115 containing the inventory items. In another embodiment, the RFIDreading terminal 100 can be further configured to display an indicator129 of the RF signal coverage over a current position aimed at by theRFID reading terminal, as schematically shown in FIG. 8.

In one embodiment, the RFID reading terminal 100 can be furtherconfigured to display a scan trace overlaid over an image of a physicalstructure (e.g., a shelf) containing one or more scanned items and oneor more items to be scanned. In one embodiment, the image of thephysical structure containing the inventory items can be received by theRFID reading terminal 100 over the network from an external computer. Inanother embodiment, the RFID reading terminal 100 can comprise atwo-dimensional imager, and the image of the physical structurecontaining the inventory items can be acquired by the two-dimensionalimager. In another embodiment, the image of the physical structure isdrawn, with appropriate detail, on the RFID reading terminal display,based on a description of the physical structure received by theterminal 100 via the user interface, from an external peripheral deviceor from an external computer.

In one embodiment, the items which have already been scanned and whichhave not yet been scanned can be displayed in two different colors, asschematically shown in FIG. 9. In another embodiment, the items whichhave already been scanned and which have not yet been scanned can bedisplayed using two different transparency patterns, as schematicallyshown in FIGS. 10-11. In one embodiment, a part of the physicalstructure (e.g., shelves or sections of shelves) containing inventoryitems having not been fully reconciled against the inventory list can beshown using a transparent pattern. In another embodiment, schematicallyshown in FIG. 12, multiple colors and/or transparency pattern can beused to display parts of physical structure containing the inventoryitems which have been fully reconciled, partially reconciled, orcontaining no items having been reconciled. In a yet another embodiment,schematically shown in FIG. 13, quantities of reconciled items can bedisplayed associated with groups of inventory items. Various embodimentsdisplaying scan traces and showing the quantities of inventory items bythe RFID reading terminal 100 are shown in FIGS. 14-19.

In one embodiment, schematically shown in FIG. 20, the RFID readingterminal 100 can be further configured to receive from an externalcomputer and to display a floor plan of the manufacturing, retail and/orstorage facility. The RFID reading terminal can be further configured todisplay its position on the floor plan. The RFID reading terminal can befurther configured to display in two or more different colors one ormore areas containing the items which have already been scanned and oneor more areas containing the items which have not yet been scanned .

In a further aspect, RFID reading device 333 can be compliant with EPC™Class-1 Generation-2 UHF RFID Protocol for Communications at 860 MHz-960MHz by EPCglobal, commonly known as the “Gen 2” standard, which definesphysical and logical requirements for a passive-backscatter,interrogator-talks-first (ITF) RFID system operating in the 860 MHz-960MHz frequency range.

In one embodiment, RFID reading terminal 100 can transmit information toa passive RFID tag by modulating an RF signal in the 860-960 MHzfrequency range. An RFID tag can receive both information and operatingenergy from the RF signal transmitted by the RFID reading terminal 100.RFID reading terminal 100 can receive information from the RFID tag bytransmitting a continuous-wave (CW) RF signal to the RFID tag.“Continuous wave” can refer to any waveform transmitted by an RFIDreading device and suitable to power a passive RFID tag, e.g., asinusoid at a given frequency. The RFID tag can respond by modulatingthe reflection coefficient of its antenna, thus backscattering aninformation signal to the RFID reading terminal 100. In one embodiment,the RFID tag can modulate the reflection coefficient of its antenna onlyresponsive to receiving an RFID signal from RFID reading terminal 100.

In a further aspect, RFID reading terminal 100 can be configured to sendinformation to one or more RFID tags by modulating an RF carrier usingdouble-sideband amplitude shift keying (DSB-ASK), single-sidebandamplitude shift keying (DSB-ASK), or phase-reversal amplitudeshift-keying (PR-ASK) using a pulse-interval encoding (PIE) format. RFIDtags can receive their operating energy from the same modulated RFcarrier.

The RFID reading terminal 100 can be configured to receive informationfrom an RFID tag by transmitting an unmodulated RF carrier and listeningfor a backscatter reply. RFID tags can transmit information bybackscatter-modulating the amplitude and/or phase of the RFID carrier.RFID tags can encode the backscattered data using, e.g., FM0 baseband orMiller modulation of a subcarrier at the data rate. The encoding methodto be employed by an RFID tag can be selected by the RFID readingterminal 100.

In another aspect, RFID reading terminal can establish one or moresessions with one or more RFID tags. An RFID tag can support at leastone session-dependent flag for every session. The session-dependent flagcan have two states. An RFID tag can invert a session-dependent flagresponsive to receiving a command from RFID reading terminal 100. Tagresources other than session-dependent flags can be shared amongsessions. In another aspect, an RFID tag can support a selected statusflag indicating that the tag was selected by the RFID reading terminal100.

Responsive to receiving an interrogation signal transmitted by the RFIDreading terminal 100, an RFID tag can transmit a response signal back toRFID reading terminal 100. The response signal can contain useful data,e.g., an Electronic Product Code (EPC) identifier, or a tag identifier(TID). The response signal can include a representation of a binarystring, at least part of which is equal to at least part one of thespecified one or more target item identifiers.

In one embodiment, RFID reading terminal can implement EPC™ Class-1Generation-2 UHF RFID Protocol for Communications at 860 MHz-960 MHz byEPCglobal. The RFID reading terminal 100 can interrogate RFID tags usingthe commands described herein infra.

Select command can be used by the RFID reading terminal 100 to select aparticular RFID tag population for the subsequent inventory round.Select command can be applied successively to select a particular tagpopulation based on user-specified criteria. Select command can includethe following parameters:

-   -   Target parameter indicates whether Select command modifies a        tag's SL flag or Inventoried flag, and in the latter case it        further specifies one of four available sessions (S0, . . , S3);    -   Action parameter indicates whether matching tags assert or        deassert SL flag, or set their Inventoried flag to A or B state;        tags conforming to the contents of MemBank, Pointer, Length, and        Mask parameters are considered to be matching;    -   Mask parameter contains a bit string that a tag should compare        to a memory location specified by MemBank, Pointer, and Length        parameters;    -   MemBank parameter specifies the memory bank to which Mask        parameter refers (EPC, TID, or User);    -   Pointer parameter specifies a memory start location for Mask;    -   Length parameter specifies the number of bits of memory for        Mask; if Length is equal to zero, all tags are considered        matching.

Inventory command set can be used by the RFID reading terminal 100 tosingle out one or more individual tags from a group. A tag can maintainup to four simultaneous sessions and a binary Inventoried flag for eachsession. Inventory command set includes the following commands:

-   -   Query command can be used to initiate and specify an inventory        round; it contains a slot counter value (Q=0 to 15) determining        the number of slots in the round; the command also includes Sel        parameter specifying which tags should respond to the Query.    -   QueryAdjust command can be used to adjust the value of the tag's        slot counter Q without changing any other parameters;    -   QueryRep command can be used to repeat the last Query command;    -   Ack command can be used to acknowledge a tag's response;    -   NAK command can be used to force a tag to change its state to        Arbitrate.

An RFID tag can implement a state machine. Once energized, a tag canchange its current state to Ready. A selected tag can, responsive toreceiving Query command, select a random integer from the range of [0;2^(Q-1)]. If the value of zero is selected, the tag can transition toReply state, backscattering a 16-bit random number. If a non-zero valueis selected, the tag can load the selected random integer into its slotcounter and change its state to Arbitrate.

Responsive to receiving the tag transmission, RFID reading terminal canacknowledge it with Ack command containing the same random number.Responsive to receiving Ack command, the tag can change its state toAcknowledged and backscatter its protocol control (PC) bits, EPC andcyclic redundancy check (CRC) value. Unacknowledged tag can select a newrandom integer from the range of [0; 2^(Q-1)], load the value into itsslot counter, and change its state to Arbitrate. Responsive to receivingQueryAdjust command, a tag in the Arbitrate state should decrement thevalue of its slot counter and backscatter its protocol control (PC)bits, EPC and CRC value if its slot counter is equal to zero.

Responsive to receiving the tag's transmission of its PC, EPC and 16-bitCRC value, RFID reading terminal can send a QueryAdjust command causingthe tag to invert its Inventoried flag and to transition to Ready state.

Access command set can be used by the RFID reading terminal 100 forcommunicating with (reading from and writing to) a tag. An individualtag must be uniquely identified prior to access. Access command setincludes the following commands: ReqRn command can be used by the RFIDreading terminal 100 to request a handle from a tag; the handle can beused in the subsequent Access command set commands. Responsive toreceiving Req_RN commands, a tag returns a 16-bit random integer(handle) and transitions from Acknowledged to Open or Secured state.

Read command can be used by the RFID reading terminal 100 to read tag'sReserved, EPC, TID and User memory;

Write command can be used by the RFID reading terminal 100 to write totag's Reserved, EPC, TID and User memory;

Kill command can be used by the RFID reading terminal 100 to permanentlydisable a tag;

Lock command can be used by the RFID reading terminal 100 to lockpasswords preventing subsequent read or write operations; lockindividual memory banks preventing subsequent write operations;permanently lock the lock status of passwords or memory banks;

Access command can be used by the RFID reading terminal 100 to cause atag having a non-zero access password to transition from Open to Securedstate.

A skilled artisan would appreciate the fact that other methods ofinterrogating RFID tags by the RFID reading terminal 100 are within thescope of this disclosure.

One embodiment of the RFID reading terminal 100 is schematically shownin FIGS. 21a (front panel view), 21 b (side panel view), and 21 c(bottom panel view). The RFID reading terminal 100 can comprise ahousing 52 within which other components of the RFID reading terminal100 can be disposed. An LCD screen display with a touch screen sensor554 can be disposed on the front panel 556. Also disposed on the frontpanel 556 can be a decode LED 558, a scan LED 559, and a keyboard 64including a scan key 568 and navigation keys 72. An imaging window 74can be disposed on the top panel of housing 52. Disposed on the sidepanel (best viewed in FIG. 21b ) can be an infra-red communication port76, an access door to a secure digital (SD) memory interface 78, anaudio jack 80, and a hand strap 82. Disposed on the bottom panel (bestviewed in FIG. 22c ) can be a multi-pin mechanical connector 84 and ahand strap clip 86. RFID reading device (not shown in FIGS. 21a-21c )can be disposed within the housing 52.

Point-Based Scan Path Determination

Other embodiments of the present application use a handheld RFID readerwith integrated barcode scanner (either laser or imager barcodescanner), and a graphical display. No additional hardware modificationsmay be necessary. A software application executes on the RFID handhelddevice processor, to provide a user interface and control the barcodescanner.

To use this system, each retail fixture requires mounting of one or morecustom decodable indicia (e.g., barcode) labels 2104 on the fixture2101. It should be noted that any decodable indicia can be employed.However, for ease of explanation and illustration, the below embodimentsare described using barcodes. It should be understood that decodableindicia other than barcodes could be used (e.g., RFID tags, etc.) aslong as the decodable indicia

There may be at least two types of custom barcode labels: an initialpoint barcode label 2102 containing data to describe the physicalcharacteristics of the fixture 2101, and multiple custom locationbarcode labels 2104 indicating locations or reference points on thefixture 2101.

Additionally, it is noted that the output (e.g., laser) of the barcodescanner travels substantially in the same direction as the radiationpattern outputted by the RFID reader of the handheld device. In thisregard, when the handheld device is pointed at the barcode label 2104,the handheld device also reads RFID tags located in an area proximate tothe barcode label 2104. This allows the user to be guided along a pathusing the barcode labels 2104 in a particular order to force thehandheld device to scan in a certain scan path 2106.

This is exemplified in FIG. 21. As a user moves the handheld RFID reader2100 while inventorying the fixture 2101 (e.g., the user points theradiation pattern of the handheld RFID reader 2100 toward a first pointof the fixture 2101), the user interface (not shown) prompts the user tobarcode scan the custom location barcode labels 2104 in a particularorder. As each such location barcode label is scanned in the definedorder, the software application on the handheld device records the dataand time of the barcode label 2104 at which the barcode label 2104 wasscanned.

As mentioned above, the barcode labels 2104 are scanned in a particularorder. For example, in FIG. 22A, the barcodes are scanned by the RFIDreader first (after the reader is moved to S1,L location) from S1,L toS1,R and then from S1,R to S2, R and then from S2,R to S2,L and thenfrom S2,L to S3,L and finally from S3,L to S3,R. This is illustrated byscan path 2106. User feedback may be received indicating a successfulbarcode scan and the user may wait to receive feedback of successfulscan before continuing RFID tag inventory (e.g., before scanning eachsuccessive barcode). The scan path 2106 assumes the handheld RFID readeris being conveyed in a substantially straight line therebetween, butthis is not required (in one embodiment). Nonetheless, the scan path2106 allows the RFID reader to scan directly over the correct path forminimizing read errors or missing RFID tags of items intended forinventorying.

As mentioned above, the data and time of the barcode label 2104 at whichthe barcode label 2104 was scanned is recorded by the handheld deviceand this data pair is entered into a table, with each row indicating adiscrete point on the continuous scan path followed by the handheld RFIDreader as the retail fixture is inventoried. An example of such table isillustrated in FIG. 22B. As shown, there is a timestamp for eachrespective barcode label (i.e., 00:05 for S1,L, 00:10 for S1,R, etc.).This method allows for verification of the rate at which the RFID readeris moved, as well as the scan path, and degree of RFID tag coverageachieved on the retail fixture.

In this regard, the handheld reader can estimate the scan path 2106 anddisplay the same to the user to determine the path scanned, as well asindicate any missed areas. To do this, the system assumes the user movesthe RFID reader 2100 at a predetermined rate (e.g., one foot/second).Using initial point fixture data, the time between scanning successivecustom barcode labels is determined whether or not as reasonable. If so,then the system draws a line indicating scan path between the barcodelabels 2104 on the display screen of the handheld device 2100. On theotherhand if the time between scans is not reasonable (e.g., the time isgreater than a first predefined threshold or lower than a secondpredefined threshold).

FIG. 23A illustrates the locations of the barcode labels 2104 inaccordance with one embodiment. As shown, at least some of the barcodelabels 2104 should be placed along the path that the user wishes to scanfor RFID tags. For example, the barcode labels 2104 should be onopposing ends of RFID tags that are intended to be scanned since theRFID handheld device should be moved between the two barcode labels2104, which is also the location of RFID tags.

It should be noted that each of the items shown on the fixture 2101 mayhave RFID tags even though the RFID tags are not explicitly visible inthe Figures. For example, the figures show jeans on the shelves of thefixture 2101 and each pair of jeans may have an RFID tag attachedthereto and associated with such pair of jeans. Thus, when eachrespective RFID tag is scanned and the data from the RFID tag isdetermined, the user determines that the jeans associated with thescanned RFID tag is present on the inventory.

It is noted that the custom barcode label may be mounted at locationseasily acquired with a barcode scanner, such as the edge of the shelf asshown in the Figures. Information encoded in each barcode must matchmounting location in accordance with some embodiments. For example, ifthe barcode data=“S1,L” or “Shelf 1, left side”, then barcode should bemounted at the left side of the first shelf. Mislocated barcode labelsmay degrade the accuracy of depicted scan path of handheld RFID readersince the system is preprogrammed with particular locations of thebarcode labels.

It should be also noted that the initial point barcode label 2102 maycontain a physical, meta-description of the fixture, such as the shapeof the fixture, the number of shelves of the fixture, physicaldimensions of the fixture, etc. The initial point barcode label 2102 maybe used during processing to validate motion between “points” (i.e.custom barcode labels).

The initial point barcode label 2102 may also be used to verify whatportion of fixture has been inventoried by handheld RFID reader. Thescan path point table (e.g., the table in FIG. 22B) should contain datafor all shelves or other areas of the fixture in the correct sequence.For example, in FIG. 22A, S1,L to S2,L indicates shelf #1 was notinventoried, and S1.L to S1,R scanned below a predetermined threshold(e.g., one second) indicates a rate of motion of RFID reader that wastoo fast and inventory errors are likely since it is likely thatinterrogation signals were not able to allow the RFID to respond or theRFID reader was unable to read the response due to the movement.

While the present invention has been particularly shown and describedwith reference to certain exemplary embodiments, it will be understoodby one skilled in the art that various changes in detail may be affectedtherein without departing from the spirit and scope of the invention asdefined by claims that can be supported by the written description anddrawings. Further, where exemplary embodiments are described withreference to a certain number of elements it will be understood that theexemplary embodiments can be practiced utilizing less than the certainnumber of elements.

A small sample of systems, methods, and apparata that are describedherein is as follows:

A1. A portable radio-frequency identifier (RFID) reading terminalcomprising:

a microprocessor;

a memory;

an RFID reading device comprising a radio frequency (RF) antenna;

a display;

wherein said portable RFID reading terminal is configured to display ascan trace; and

wherein said scan trace is provided by a line comprising a plurality oftime varying points, each point being defined by a projection of acoverage shape of an RF signal transmitted by said RFID reading deviceonto a chosen plane at a given moment in time.

A2. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is configured, by reading RFID tags attached tosaid items, to reconcile an inventory of items stored in a facilityagainst at least one of: an expected inventory list, an expected countof items.

A3. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is configured , by reading RFID tags attached tosaid items, to reconcile an inventory of items stored in a facilityagainst at least one of: an expected inventory list, an expected countof items; and

wherein said RFID terminal is configured to receive from an externalcomputer at least one of: said expected inventory list, said expectedcount of items.

A4. The portable RFID reading terminal of (A1), further comprising auser interface;

wherein said portable RFID reading terminal is configured, by readingRFID tags attached to said items, to reconcile an inventory of itemsstored in a facility against at least one of: an expected inventorylist, an expected count of items; and

wherein said RFID terminal is configured to receive via said userinterface at least one of: said expected inventory list, said expectedcount of items.

A5. The portable RFID reading terminal of (A1), further comprising atwo-dimensional imager;

wherein said portable RFID reading terminal is configured, by readingRFID tags attached to said items, to reconcile an inventory of itemsstored in a facility against at least one of: an expected inventorylist, an expected count of items; and

wherein said RFID terminal is configured to receive via saidtwo-dimensional imager at least one of: said expected inventory list,said expected count of items.

A6. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is configured, by reading RFID tags attached tosaid items, to reconcile an inventory of items stored in a facilityagainst at least one of: an expected inventory list, an expected countof items; and

wherein said RFID terminal is configured to receive from an externalmemory device at least one of: said expected inventory list, saidexpected count of items.

A7. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is configured, by reading RFID tags attached tosaid items, to reconcile an inventory of items stored in a facilityagainst at least one of: an expected inventory list, an expected countof items; and

wherein said RFID terminal is configured to receive from a firstexternal computer at least one of: said expected inventory list, saidexpected count of items; and

wherein said RFID terminal is further configured to transmit to a secondexternal computer at least one of: a list of read RFID tags, a count ofread RFID tags.

A8. The portable RFID reading terminal of (A1), further comprising atwo-dimensional imager;

wherein said portable RFID reading terminal is further configured todetermine a spatial position of said RF signal coverage shape based on aknown position and orientation of said RF antenna relatively to aposition of a field of view of said two-dimensional imager.

A9. The portable RFID reading terminal of (A1), further comprising atwo-dimensional imager;

wherein said portable RFID reading terminal is further configured tomeasure a distance to an object using said two-dimensional imager; and

wherein said portable RFID reading terminal is further configured todetermine and display a projection of said RF signal coverage shape ontothe plane defined by a physical structure.

A10. The portable RFID reading terminal of (A1), further comprising atleast one accelerometer;

wherein said portable RFID reading terminal is further configured todetermine a change of a spatial position and orientation of said RFsignal coverage shape based on proper acceleration values received fromsaid at least one accelerometer.

A11. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is further configured to display at least one of:a quantity of scanned items, a quantity of items which have not bescanned yet, a total quantity of items to be scanned.

A 12. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is further configured to display an indicator of aratio of quantity of scanned items to a total quantity of items to bescanned.

A13. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is further configured to display said scan traceoverlaid over an image of a physical structure.

A14. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is further configured to receive an image of aphysical structure; and

wherein said portable RFID reading terminal is further configured todisplay said scan trace overlaid over said image of said physicalstructure.

A15. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is further configured to receive a description ofa physical structure;

wherein said portable RFID reading terminal is further configured tocreate an image of said physical structure based on said description;and

wherein said portable RFID reading terminal is further configured todisplay said scan trace overlaid over said image of said physicalstructure.

A16. The portable RFID reading terminal of (A1), further comprising atwo-dimensional imager;

wherein said portable RFID reading terminal is further configured, usingsaid two-dimensional imager, to acquire an image of a physicalstructure; and

wherein said portable RFID reading terminal is further configured todisplay said scan trace overlaid over said image of said physicalstructure.

A17. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is further configured to display an indicator ofan RF signal coverage over said scan trace overlaid over an image of aphysical structure.

A18. The portable RFID reading terminal of (A1), wherein said portableRFID reading terminal is further configured to display a indicator of anRF signal coverage over a current position within said scan trace.

The invention claimed is:
 1. A system for reading RFID tags, the systemcomprising: a barcode reader that projects a light to read barcodesattached to an object in a predetermined sequential order; an RFIDreader comprising an antenna that reads RFID tags while the barcodereader moves to sequentially read the barcodes in the predeterminedsequential order along the object; and wherein an RFID scan path of theobject is determined based on scanning the barcodes in the predeterminedsequential order.
 2. The system of claim 1, wherein a radiation patternof the RFID reader projects in a direction substantially similar to thedirection of the barcode reader laser.
 3. The system of claim 1, whereinsaid portable RFID reading terminal is configured, by reading RFID tagsattached to said items, to reconcile an inventory of items stored in afacility against at least one of: an expected inventory list, anexpected count of items; and wherein said RFID terminal is configured toreceive from an external computer at least one of: said expectedinventory list, said expected count of items.
 4. The system of claim 1,further comprising a user interface; wherein said portable RFID readingterminal is configured, by reading RFID tags attached to said items, toreconcile an inventory of items stored in a facility against at leastone of: an expected inventory list, an expected count of items; andwherein said RFID terminal is configured to receive via said userinterface at least one of: said expected inventory list, said expectedcount of items.
 5. The system of claim 1, further comprising atwo-dimensional imager; wherein said portable RFID reading terminal isconfigured, by reading RFID tags attached to said items, to reconcile aninventory of items stored in a facility against at least one of: anexpected inventory list, an expected count of items; and wherein saidRFID terminal is configured to receive via said two-dimensional imagerat least one of: said expected inventory list, said expected count ofitems.
 6. The system of claim 1, wherein said portable RFID readingterminal is configured, by reading RFID tags attached to said items, toreconcile an inventory of items stored in a facility against at leastone of: an expected inventory list, an expected count of items; andwherein said RFID terminal is configured to receive from an externalmemory device at least one of: said expected inventory list, saidexpected count of items.
 7. The system of claim 1, wherein said portableRFID reading terminal is configured, by reading RFID tags attached tosaid items, to reconcile an inventory of items stored in a facilityagainst at least one of: an expected inventory list, an expected countof items; and wherein said RFID terminal is configured to receive from afirst external computer at least one of: said expected inventory list,said expected count of items; and wherein said RFID terminal is furtherconfigured to transmit to a second external computer at least one of: alist of read RFID tags, a count of read RFID tags.
 8. The system ofclaim 1, wherein said portable RFID reading terminal is configured, byreading RFID tags attached to said items, to reconcile an inventory ofitems stored in a facility against at least one of: an expectedinventory list, an expected count of items; and wherein said RFIDterminal is configured to receive from an external computer at least oneof: said expected inventory list, said expected count of items; andwherein said RFID terminal is further configured to transmit to saidexternal computer at least one of: a list of read RFID tags, a count ofread RFID tags.
 9. The system of claim 1, further comprising atwo-dimensional imager; wherein said portable RFID reading terminal isfurther configured to determine a spatial position of said RF signalcoverage shape based on a known position and orientation of said RFantenna relatively to a position of a field of view of saidtwo-dimensional imager.
 10. The system of claim 1, further comprising atwo-dimensional imager; wherein said portable RFID reading terminal isfurther configured to measure a distance to an object using saidtwo-dimensional imager; and wherein said portable RFID reading terminalis further configured to determine and display a projection of said RFsignal coverage shape onto the plane defined by a physical structure.11. The system of claim 1, further comprising at least oneaccelerometer; wherein said portable RFID reading terminal is furtherconfigured to determine a change of a spatial position and orientationof said RF signal coverage shape based on proper acceleration valuesreceived from said at least one accelerometer.
 12. The system of claim1, wherein said portable RFID reading terminal is further configured todisplay at least one of: a quantity of scanned items, a quantity ofitems which have not be scanned yet, a total quantity of items to bescanned.
 13. The system of claim 1, wherein said portable RFID readingterminal is further configured to display an indicator of a ratio ofquantity of scanned items to a total quantity of items to be scanned.14. The system of claim 1, wherein said portable RFID reading terminalis further configured to display said scan trace overlaid over an imageof a physical structure.
 15. The portable RFID reading terminal of claim1, wherein said portable RFID reading terminal is further configured toreceive an image of a physical structure; and wherein said portable RFIDreading terminal is further configured to display said scan traceoverlaid over said image of said physical structure.
 16. The portableRFID reading terminal of claim 1, wherein said portable RFID readingterminal is further configured to receive a description of a physicalstructure; wherein said portable RFID reading terminal is furtherconfigured to create an image of said physical structure based on saiddescription; and wherein said portable RFID reading terminal is furtherconfigured to display said scan trace overlaid over said image of saidphysical structure.
 17. The system of claim 1, further comprising atwo-dimensional imager; wherein said portable RFID reading terminal isfurther configured, using said two-dimensional imager, to acquire animage of a physical structure; and wherein said portable RFID readingterminal is further configured to display said scan trace overlaid oversaid image of said physical structure.
 18. The system of claim 1,wherein said portable RFID reading terminal is further configured todisplay an indicator of an RF signal coverage over said scan traceoverlaid over an image of a physical structure.
 19. The system of claim1, wherein said portable RFID reading terminal is further configured todisplay a indicator of an RF signal coverage over a current positionwithin said scan trace.
 20. A method of reading RFID tags, comprising:providing a device that can read barcodes and RFID tags, wherein thebarcodes are attached to an object and respectively having apredetermined sequential read order; while reading the barcodes in thepredetermined sequential read order, outputting an interrogation signalto RFID tags so that the RFID tags can be read while the barcode readermoves to sequentially read the barcodes in the predetermined sequentialorder; determining a scan path of the RFID reader based on scanning thebarcodes in the predetermined sequential order.